Remember "Flipper"? The popular TV show about a Florida park ranger and his family's pet dolphin aired from 1964-1967 and in reruns for many years thereafter. Portrayed by five different bottlenose dolphins, Flipper was depicted as happy, intelligent and friendly, helping the ranger and his sons through various adventures.
The stereotype of dolphins as friendly and happy has been reinforced by aquarium shows featuring trained dolphins and by "swim with the dolphins" experiences offered by aquariums, theme parks and private tour boat operators. But in fact, dolphins are incapable of changing their facial expressions. What appears to be a smile is actually a result of their permanently curved mouths and the physical configuration of their jaws, and their expression remains the same whether they are performing with a trainer or aggressively charging a rival [sources: Marino, National Geographic, Szokan].
As for their happy demeanor, activist and former dolphin trainer Ric O'Barry, who captured and trained at least one of the dolphins that portrayed television's Flipper, became so convinced that dolphins were stressed, unhappy and even depressed in captivity that he has spent the past 40 years advocating for the end of dolphin shows at theme parks and aquariums and for the release of all captive dolphins back into the wild [source: Palmer].